“A shift this significant will take some time, as it requires changes along every point of the supply chain -- from the hatchery to the processing plant," said Tim Tassopoulos, executive vice president of operations of Chick-fil-A.

Tassopoulos said the company, based in the Atlanta suburb of College Park, will begin posting quarterly updates to its website on their progress in 2015.

The company's announcement was praised by public health groups.

"Keep Antibiotics Working is happy to learn that Chick-fil-A is taking this step to meet its customers demand for meat from animals raised without unnecessary antibiotics," the group said in a statement.

The privately held company has taken other actions to improve its ingredients. It announced last year it had removed yellow dye from its chicken soup. It's also testing the removal of high fructose corn syrup from its dressings and sauces, artificial ingredients in its buns and TBHQ -- a preservative -- from its peanut oil.

Food companies and other restaurant chains have taken steps to remove controversial ingredients from their products. Last week, Subway said it would remove an ingredient used in the production of foamed plastics such as yoga mats and rubber-soled shoes from its bread.